Step 5 - Now draw splines similer to the ones in the picture below. These will be lofted and used to make edges smoother and less rigid.

Step 6 - Now you will need to copy the splines.

Step 7 - After copying the splines loft each of them individually. This may take some time.

Step 8 - Now you must type "split" into the command line. Now select your object and then one of the surfaces you just lofted.
Repeat this for the other lofted surfaces. Then delete the surfaces and cut objects. Now some of the corners should be a bit smoother instead of rigid.

Step 9 - Now you need to draw splines such as are int he picture below. These will be used for a 2 rail sweep.